1. Field of the Invention
The invention pertains to the field of medication storage and dispensing devices. More particularly, the invention pertains to a device for automatically dispensing solid medicinal units, such as pills and capsules, based upon patient needs.
2. Description of Related Art
Most medications are consumed orally. Most are distributed in two forms, pills and capsules. Since pills and capsules must be swallowed, they cannot be too small or too large. They are made in approximately 25 to 30 different sizes. Pills are shaped like a thin disk, while capsules are shaped like a cylinder with semi-spherical ends. There are at least 2,000 different drugs that must be dispensed to patients in hospitals or pharmacies, and more are developed every year. Accordingly, there is a need to automate dispensing of such drugs in a manner that is free of human error, fast, efficient, and able to handle most if not all of the different drugs that patients need.
Automated prescription filling solutions exist in the art. The most advanced of these incorporate robotic techniques to dispense tablets or capsules into vials. Still, medication-dispensing technology has, in some instances, had to sacrifice some level of compactness to achieve accurate and efficient dispensing of drugs while storing ample reserves of the same for future dispensing. For example, the medicament-dispensing cell disclosed in U.S. Pat. No. 6,085,938 includes a medicament storage section, a rotatable platen, and a dispensing assembly for conveying medicament in single file from the storage section to the discharge section. The width of the storage section is significantly greater than the width of the medicaments, however, such that typically the system built upon the device, such as the SCRIPTPRO SP 200 system, contains only approximately 200 medication dispensing cells. Additionally, in the storage section the pills or capsules are grouped together such that, during storage and handling, and when a pill is extracted, the other pills move and rub against each other. Such rubbing can cause flaking or erosion at the side of the medicament, and dust from one medication could stick to another absent thorough cleaning of the cell and mechanism.
The automatic medicament dispensing system disclosed in U.S. Pat. No. 5,337,919 includes a number of medication-dispensing cells, as well as memory associated with the controller for storing cell data, including the location of, and medicament assigned to, each cell. In operation, the system controller receives instructions for a prescription including the medication and quantity to be dispensed. The controller then moves a manipulator arm to the appropriate cell as indicated by the cell data, and transfers the medication from the cell into a vial. A problem can develop, however, if the cell data is incorrect or the locations of the various cells have been changed. Such might occur, for example, if an attendant removes more than one cell for replenishment and does not replace the cells to the same locations. In such a situation, the controller would move the manipulator arm to the cell location corresponding to the cell data for the prescribed medicament. The cell at that location would not contain the medicament as indicated by the cell data and, as a result, the wrong medicament would be dispensed.
Due to the above-described and other limitations, it is desirable to provide a medicament-dispensing system that compactly stores thousands of different drugs, dispenses the drugs accurately and efficiently, minimizes the possibility of human error that would result in the wrong medication or quantity being dispensed, and stores the drugs such that they cannot move and rub against each other, and hence, are unlikely to chip, flake, powder or stick together.
This application discloses and claims an invention that is useful in conjunction with a system of the type shown and described in a commonly owned U.S. application entitled, xe2x80x9cHOSPITAL DRUG DISTRIBUTION SYSTEM,xe2x80x9d filed on the same day as the present application. That application is hereby incorporated by reference herein in its entirety.
The invention comprises a device to dispense solid medicinal units, such as pills, capsules, or the like (hereinafter, xe2x80x9cmedicinal units,xe2x80x9d or simply, xe2x80x9cunitsxe2x80x9d), automatically, based upon patient needs. In the invented device, the medicinal units are stored in long, thin tubes. Each tube stores, in single-line, vertical fashion, a series of units of the same drug. The tube is specially designed for efficient dispensing of the appropriate number of medicinal units from the bottom portion thereof Such is accomplished through use of a novel valve at the bottom of the tube.
When drug tubes become empty, they are either discarded and replaced by a full drug tube, or returned to a drug refilling center to be refilled, depending upon the embodiment. The drug refilling centers are regional operations that stock large quantities of drugs, receive orders for tubes filled with specific drugs, and deliver filled drug tubes to hospitals, pharmacies, nursing homes, or any other institution that maintains a drug distribution system utilizing the invented device. Having such regional centers refill the tubes is advantageous in that it is cost effective and efficient for drug tube refilling to be done on a large scale, preferably with automation and safeguard instrumentalities. Such automation and safeguards minimize errors, so that each drug tube is always filled with the drug as indicated by an identification means, such as a barcode label or a memory chip, affixed to the tube. Also, the use of refilling centers eliminates the expense for each pharmacy, hospital or nursing home to maintain such a refilling operation for its own needs alone.
Two embodiments of the invented apparatus are especially useful in a hospital drug distribution system, or HDDS. In one such embodiment, the tube and valve are an integrated unit. This embodiment is called the Integrated Tube-Valve, or ITV. Using an ITV makes the most sense when it is cost effective to return empty tubes to a drug refilling center for refilling. In such case, there is little advantage to disconnecting the valve prior to returning the tube for refilling, and indeed, it is advantageous that the drug refilling center test the valve portion of the ITV at the time of refilling. Such testing minimizes the frequency of valve malfunctions during subsequent HDDS operation.
In a second embodiment useful in an HDDS, the tube separates from the valve. This embodiment can be used when it is cost effective to discard empty tubes and order new ones, or when the empty tubes (without the valve) are returned to the drug refilling center for refilling. In such a case, the hospital disconnects and discards a tube when it becomes empty, orders a new tube with the same drug, and, when that new, full tube arrives, connects it to the valve. Alternatively, the hospital disconnects and returns the empty tube to the refilling center for refilling. The hospital preferably tests the valve""s solenoids prior to connecting the new tube. To ensure smooth and continuous operation of the system, each drug has a backup tube on-line at the beginning of the day. Therefore, such valves (with their connected tubes) are arranged in a group of at least twoxe2x80x94and preferably twoxe2x80x94called a valve-unit, or VU. In a VU, the valves are constructed to ensure that all tubes within the VU store the same drug, as described below.
Still another embodiment of the invented apparatus is useful in a pharmacy drug distribution system, or PDDS. In this embodiment, known as the integrated elastic valve, or IEV, the valve consists of a molded elastic rubber sleeve mounted tightly upon the lower part of the drug tube. Small holes or slits in the lower portion of the drug tube are provided to accommodate portions of the elastic rubber sleeve that act as xe2x80x9cshutterxe2x80x9d and xe2x80x9ccatcherxe2x80x9d doors controlling the dispensing of the medicinal units. Drugs are extracted, at a drug extraction station, from one tube at a time. At the extraction station, the valve is manipulated by a valve control mechanism including various solenoids. As noted, this embodiment is most useful in a PDDS, where each prescription consists of multiple units of a single medication. In such context, it is efficient to have one set of extraction solenoids (at the extraction station), and transport the needed drug tube, with its shutter and catcher doors, to the extraction station for extraction of the drugs.